The present invention relates to technology for converting a telephone number when a call is originated or received.
Japanese Patent Laid-Open Publication No. 2005-94646 (hereinafter, referred to as Patent Document 1) discloses a technology which converts a telephone number when a call is originated or received.
According to the technology disclosed in Patent Document 1, an IP (Internet Protocol) telephone number is stored by associating the IP telephone number with a PSTN (Public Switched Telephone Network) telephone number, whereby the PSTN telephone number is converted into the IP telephone number when a call is originated.